Get rid of InstallUninstallTest

Help topics test already installs and uninstalls every module. I have moved the hook help verification from InstallUninstallTest to help module so we don't lose that coverage.

That means the only coverage we lose here is trying to reinstall all modules at once after they've previously been uninstalled.

Seem test failure could be legit.

Need to ignore hidden modules.

Also I opened 📌 Add GenericModuleTestBase and use it to test general module things Downport which would handle one more bit of lost test coverage - if we add that base class, then every core module could test itself being installed, uninstalled, then installed again. No way to do that efficiently without making it a per-module test though so a bit of a bigger change.

All green!

As the finder of a reinstall bug in the past - #2534532: Cannot reinstall Forum after it was previously installed → - I am kinda sad to see this go, but if we can replace it with a generic test that can be used by all modules, that would be even better. I suppose it's a shame that data providers cannot be parallelised.

Should we not add the generic coverage suggested to replace this before / at the same time as removing it?

We could probably merge this with 📌 Add GenericModuleTestBase and use it to test general module things Downport and remove HelpTopicsSyntaxTest at the same time. However having this MR open made 📌 [PP-2] Speed up gitlab ci runs Postponed easier to work on, so let's instead postpone it on that issue, and close it once it gets done.

📌 Add GenericModuleTestBase and use it to test general module things Downport is in so this can go back to active.

📌 Add GenericModuleTestBase and use it to test general module things Downport removed InstallUninstallTest too in the end, marking this as duplicate.